nbsd@hck.sk (Juraj Hercek) writes:

>There was some interest in having undervolting feature in current 
>kernel. I did a patch some time ago which was merely a rewrite of est 
>(http://mail-index.netbsd.org/tech-kern/2006/06/10/0006.html). It wasn't 
>a way to go because of many changes needed to adjust it when something 
>changed in original est. New patch is completely different in a such way 
>that it tries to make *minimal* changes to the original est.


I also have added undervolting support recently. The code is much
simpler (and doesn't need unconst :-)) but probably a bit more
cumbersome to use.

In particular, I only have a single integer knob that sets the
undervolting for the currently active frequency. Unlike yours
the knob specifies the voltage drop and not the absolute value.
I.e. in sysctl.conf I use (Pentium M 780):

machdep.est.frequency.target=2267
machdep.est.undervolt=192
machdep.est.frequency.target=1867
machdep.est.undervolt=192
machdep.est.frequency.target=1600
machdep.est.undervolt=224
machdep.est.frequency.target=1333
machdep.est.undervolt=224
machdep.est.frequency.target=1067
machdep.est.undervolt=256
machdep.est.frequency.target=800
machdep.est.undervolt=272

I found that the mprime program is a good indicator for stability. It
is not in pkgsrc but you can find it here: http://www.mersenne.org/

-- 
-- 
                                Michael van Elst
Internet: mlelstv@serpens.de
                                "A potential Snark may lurk in every tree."